Tern GEN3 HSD S9i Sport

The Tern HSD S9i Sport is Tern’s answer for people who want serious cargo capacity without a cargo bike’s footprint. This Gen 3 build is the top of the Tern HSD lineup, with Bosch’s Smart System, wireless eShift, and a true no-maintenance drivetrain.

What makes the HSD S9i Sport a Sport build

Bosch’s Performance Sport motor puts out 90 Nm of torque and up to 600% pedal assist, with a 28 mph top speed since it’s Class 3. It runs on the Bosch Smart System, so you get the Kiox 300 display, GPS tracking, and an anti-theft alarm through the ConnectModule (comes with a free 12-month Flow+ trial). Full specs are on Tern’s official HSD S9i Sport page.
The drivetrain is the real story here: a 9-speed internal gear hub paired with Bosch eShift, which lets you shift while stopped or under load. No more mistimed shifts at a red light with a kid on the back. Add a Gates Carbon Drive belt instead of a chain, and there’s basically nothing to maintain.

Built to actually carry things

The Tern HSD S9i Sport is rated to a 419 lbs max gross vehicle weight, with 176 lbs on the rear rack alone. That’s enough for a kid, a week of groceries, or both, without the bike feeling sketchy. Magura hydraulic disc brakes and a Suntour suspension fork handle stopping and comfort when it’s loaded up.

The cockpit adjusts tool-free to fit riders from 5’0″ to 6’9″, so if two people in the house are sharing one bike, that’s not a problem.
Even fully specced out, it folds down to 166 × 42 × 87 cm in about 5 seconds. Small enough to live in a hallway, a closet, or the back of a car.

The 90 Nm is a free software update

This motor leaves the factory at 85 Nm and 600 W. Bosch’s Performance Upgrade takes it to 90 Nm and 700 W and costs nothing. You install it yourself in the Bosch Flow app, over the air. No service appointment, nothing we have to plug in.

There are two upgrades and they get mixed up constantly, including on spec sheets. The Performance Upgrade is the one that gives you 90 Nm. Performance Upgrade 2.0 is a separate, later one that raises low speed assist to as much as 600 percent and adds no torque at all. If a bike has never been updated, it is still an 85 Nm bike no matter what the listing says.

The honest trade, and Bosch says this themselves: higher settings mean more wear and less range, and you notice it first on the chain and sprockets. You set the values per riding mode, so you can run it hard when you want it and dial it back for a long day. Assist still cuts at 28 mph either way, so it stays a Class 3 bike.

Worth knowing if you are cross shopping: this is the BDU347Y Performance Line Sport. There is an older motor sold under the same Performance Sport name, the BDU338Y, that makes 75 Nm and gets no torque upgrade at all. Same words on the page, different motor. Ask us in the shop and we will show you where the code is.

Available in Thomas Green (pictured throughout) and Basalt. See the photo gallery above for both colors.
Come by the shop at 181 Brook St to see it and take it for a ride. With a cargo bike like this, you really want to feel how it handles loaded before you decide.